Method of separating electrodeposited metals from lead matrices.



' powdered gra hite which is brushed over with, wax and graphite. The for u 'edyhad-"the disadvantage or obje -tory in a1 cases and some better method of UNITED STATES CHARLES REVERDYS, or NEW YORK, N. COMPANY, or BROOKLYN, NEW YOR PATENT ()FFICE.

ASS IGNOR TO F. WESEL MANUFACTURING K, A CORPORATION OF NEW YORK.

METHOD OF BEIPARATIIIQ ELE(JTRODEIOSII'IJIED META LS FROM LEAD MATRICES.

Application filed October 25,

To all whom 'it may concern:

Be itknown that I, Crmnnns Ravnnoxs, a resident ofthe borough ofBrooklyn, of the city New York, in the State ofNew York, have iniented certain new and useful Improvements in Methods of Separating Electrodeposited Metals from Lead Matrices, of which the following is a specification; I

In the manufacture of electrotypes, .lead has toa considerable extent supplanted wax as a matrix material. In usin lead as a matrix material however, consi erable difiiculty has been experienced in separating the electrolytically formed shell on account of the ten ency of this shell and the lead matrix to unite themselves together in a substantially integral iece. It has been attempted toovercome t is difficulty by employing the surface 0 the lead matrix, previously to the production of the shell thereon, in? order to form what may be referred to as a separatirf-layer the matrix and s'helL 'T'is se aratin layer of graphite does not inter ere with the electro deposition of the metal forming the shell and in many cases the use ofgraphite in this way is satisfactory. It is extremely difficult however, where a matrix has deep cavities, for instance, such as a matrix prodf ced from a type form, to apply the gra hii e in such a way as to form an effective s a ating layer onaccount ofthe difliculty 'eaching the' deep parts with the bristles of tlhe brush and of making the graphite adhere sufficiently under the treatment which it possible to give these arts. To overconie this difiiculty an a esive substance has been employed, in addition -to the graphit such as a solutiomof beeswax inbenzin, but this remtion that the s olution' would accnu'iulatc in st rail cavities and would become concentrate on account of the'evaporation of the b zin so that some cavities would become fi ed up ation therefore of a separating layer of grahite between the lead matrix and the electr ytlcally de sited-shell has not been satis crendering easy the separation of the shell and matrix has been sought.

The object of the present invention is to provide such a method.

In its broad aspect, the invention consists Specification of Letters Patent.

Patented Nov. 10, 19 08. 1901. Serial No. 399,078.

in treating the surface of the lead matrix with some substance which can easily pene trate the remoter and smaller cavities of the matrix and will react with the lead to form a thin film there m-consisting of somesalt of lead depending upon the particular substance employed to react therewith, which thin film will not interfere with the electro-deposition upon the surface ofthe matrix but which Wlll be effective'in render- -ing-the separation of the shell subsequent to its-formation, easy and convenient. I have discovered that for this purpose the lead rii'atrix may be treated with carbonic acid to produce a thin film of carbonate of lead thereon which fulfils all of the conditions.

Many different means may be employed for applying the carbonic acid to the surface 0 the ead matrix, as will be obvious. 'llhLlead matrix, -.may, for instance, be placedin a closed box in which carbonic acid maybe generated from marble dust and a dilute mineral acid such as muriatic acid,the

marble dust and acid generating carbonic acid gas which attacks the surface of the lead matrix, even to the remotest and smallest cavities while in a still nascent condition. I prefer, however, to employ carbonic acid as to the matrix in the presence of heat in order to expedite the reaction and for this pur use I may jet the gas upon the surface of t e matrix by an air blast or b the use of steam. In this way the acid is driven with considerable force into the deepest and smallest cavities and under the action of the heat immediately enerates the superficial film of carbonate 0 lead. Moreover, I may also facilitate the separation of the matrix and shell by employin in addition to the carbonic acid or in ad ition to the carbonic acid and stean'n an oily or fatty substance suchas paraflin oil or an alcoholic solution of rosin, the blast of the gas, in Slu'h a case cntraining the oily substance so that it is sprayed upon the surface of the matrix to-' gether with the gas.

It has been found in practice that by the treatment which has just been described, an exceedingly lhiu film is formed over the surface of the loud matrix which does not interfere at all with the clootro-dcymsition of metal thereon and which greatly facilitates the scpzn'ation of the shell soon as it is; formed. Furthoru'iorv, admirable results have boon ohlniuml pill-limilalrly with mntf rices having deeply seated recesses and small cavities which were not only diilicnlt but practically impossible to reach with the old graphite methods.

It will be understood that the invention is not limited to the employment of an oily substance, or to the use of steam or compressed air or to the employment of heat, but that these features of the described method have simply been found to be preferable in obtaining the best results and in accelerating 'or expediting the reaction. Moreover, the invention is not limited to the use of carbonic acid or to the formation of carbonates, as it is possible that other thin films may be formed upon the surface of the lead matrixby. employing some other substance capable of reacting with the lead to produce a thin film which satisfies the necessary conditions. Furthermore, it should bementioned that the word film has been without any particularsignificance in so far as this term might be. taken to describe the structure of the deposit formed upon the surface of the matrix. In other words,-the word film is used as a reference to the deposit rather than as a term defining the.

particular nature of the deposit. Applicant has not determined whether this deposit is in the nature of a cohesive coating as the term film mi ht imply or .whether it is composed of' iso ated or separate particles, or whet-her under different conditions the structure of this deposit might be varied.

It will be understood that the method is applicable to the treatment of lead matrices which are designed to be used for any and every purpose as well as forlead matrices which are used in the manufacture of electrotypes as referred to at the beginning of this specification.

I claim 1. -'lhe herein described method of treating lead matrices which method consists in producing by the action of a suitable gas upon the surface of the matrix a film of, a.

production of the sists in treating the surface of a lead matrix with a gas which will react with the lead to form a lead'salt upon the surface previously to the producing of the electrodeposit thereon.

4. The herein described method which consists in treating the surface of a lead matrix with carbonic acid to form a thin film of carbonate of land upon the surface of the' matrix previously to the production of the electro-depositthereon. used throughout the description and claims 5. The herein described methodwhich consists in treating the surface of a lead'matrixwith a blast of carbonic acid previously .to the producing of theele'ctro-deposit thereon.

6. The herein described method which consists in treating the surface of a lead matrix with carbonic acid and steam previously to the production of the electro-deposit thereon; 7. The herein described method which consists in treating the surfaceof a lead matrix by sprayin upon the surface of the lead n'iatrix car onic acid commingled' with an oily or fatty substance previously tothe pro duction of the electro-deposit thereon. r

8. The herein described method which con- --sists in treating the surface of a lead matrix by spraying upon the lead matrix a mixture of carbonic acid, steam and tparaflin .oil previously to the production 0 the electro-deposit thereon. f

.This specification signed and witnessed this '22nd' day of October, 1907..

" CHARLES, REVERDYS.

Signed in the presence -of ALFRED W. KIDDLE, MARJORIE RoLL'iNs. 

